Senior space agency managers who ordered the launch of the shuttle Challenger last month denied yesterday that they pressured the manufacturer of the shuttle's booster rockets to reverse its initial opposition to the launch.

National Aeronautics and Space Administration officials also testified to a presidential investigating commission that they never told superiors -- the men responsible for the final decision to launch on Jan. 28 -- about flight safety concerns raised by the manufacturer. It was unnecessary to inform them, the officials said.

It was not part of the "operating mode," said Stanley Reinartz, manager of shuttle propulsion projects for NASA. "For better or worse, I did not perceive any clear requirement for interaction with Level 2," he said, referring to the officials above him in the agency hierarchy.

The disclosure was one of several in commission testimony yesterday concerning failures of communication before the launch that took the lives of the seven Challenger crew members.

The space agency officials said they were not told that engineers at Morton Thiokol Inc. continued to unanimously oppose the launch, because of their concern about the effect of cold on the booster's seals, after the company itself had formally approved the mission.

No Thiokol official offered the possibly crucial information that the engineers were still opposed, the officials testified. One NASA manager testified that had he known this, he would not have agreed to the launch.

One senior space agency official, who first heard of the engineers' fears, said he told his superior and recommended that that official pass the warning higher. This was never done.

In addition, NASA officials testified when a key Thiokol engineer passed along information about the performance of rubbery seals in the booster joints, they took it as support for the decision to launch. The engineer testifed Tuesday that he was deeply opposed to the launch and that his information was in support of that opposition.

Finally, a NASA ice inspection team said that although they found the now-suspect right booster to have a prelaunch temperature of only 19 degrees Fahrenheit, they did not report this to superiors because they did not think it was unacceptable.

Much of the testimony yesterday seemed to exasperate the presidential commission, headed by William P. Rogers. Its original low-key demeanor has all but evaporated in the past two days.

"Mr. Reinartz," said Robert Hotz, a former publisher of Aviation Week magazine, "are you telling us that you in fact are the person who made the decision not to escalate this to a Level 2?"

"That's correct, sir," replied Reinartz.

"Do you think the system should be changed?" asked Rogers.

" . . . I would like the opportunity to study that question," the witness said.

Rogers suggested that there had been "a breakdown" in NASA's decision-making process.

Yesterday's testimony followed statements Tuesday by Thiokol engineers that they felt "pressured" by NASA to reverse their original objections to the flight and that company managers, apparently reacting to the pressure, authorized the launch against the engineers' unanimous position.

Lawrence Mulloy, manager of NASA's solid rocket booster project, acknowledged yesterday during more than three hours of testimony that he had vigorously questioned Thiokol's original recommendation against launching the shuttle.

But he said, "I certainly don't consider it to be applying pressure."

Mulloy, portrayed by Thiokol engineers and managers as pressing them to reconsider their crucial no-launch decision, said, "The recommendation to launch or not to launch wouldn't upset me one way or the other."

Under questioning by commissioners, Mulloy said he was surprised by Thiokol vice president Joe C. Kilminster's first recommendation against a launch because it seemed to Mulloy that the company had not presented sufficient engineering data to back up its position.

Kilminster's "conclusions," he said, were "without basis and I challenged them. That has been interpreted as pressure. I certainly don't consider it to be applying pressure. Any time one of my contractors come to me with a recommendation, I probe to assure that it is sound and logical. This was a rather surprising conclusion [against a launch], so I challenged that."

Thiokol witnesses had cited as an exmaple of pressure a NASA official's statement that he was "appalled" at the initial recommendation against the launch.

Yesterday, George Hardy, deputy director of science and engineering at NASA's Marshall Space Flight Center, conceded that he had used the word "appalled" but in a different context than that suggested by the Thiokol witnesses.

"I stated I was somewhat appalled," Hardy said, "and that was referring specifically to the interpretation of some of the data that Thiokol had presented . . . . " rather than to the recommendation against the launch.

Denying he pressured Thiokol to change its recommendation, Hardy said he was merely following his routine practice of challenging engineer's interpretations of data "to test the degree of understanding of the individual who is presenting the data."

He disputed testimony by Thiokol officials that during the pre-launch discussions, NASA had departed from traditional practice by requiring the engineers to prove that the flight might be unsafe.

"I categorically reject any suggestion" that his method of challenging data is "opposed to the traditional approach of proof that this craft is ready to fly," Hardy declared.

Describing the eventual decision by Thiokol to support a launch, Hardy said, "I did not detect any dissent when Thiokol came back with their final recommendation. If I had been conscious of the fact that there were 20 percent or 25 percent, or anything like that, of opinions that were contrary to the recommendations that was made, I would have pursued that with the individuals involved."

Reinartz said the discussion of Thiokol's warnings was "thorough and professional." But he said he did not know Thiokol's engineers were unanimous in opposing launch.

"At the end of the 2 1/2 hour [teleconference] period and after their [Thiokol's] final recommendation to launch, I collectively asked all telecon parties if there were any disagreements," Reinartz said. "There were none received from Thiokol . . . . " he said.

Reinartz said he did not know of the Thiokol memos warning of seal problems, and that he was unaware of the "internal dissension" at Thiokol the night before the launch.

In any event, he said, "I was satisfied that there was not a flight safety problem."

The discussions between NASA and Thiokol began late the afternoon before the launch when company engineers warned Judson Lovingood, Reinartz's deputy, that they were concerned about cold temperatures.

On the basis of that discussion, Lovingood testified, "I felt like that we were probably approaching a launch delay." Lovingood said he told Reinartz about Thiokol's concerns and recommended that Reinartz advise his superior, Arnold Aldrich, shuttle program manager, that it might be necessary to delay the shuttle launch until temperatures warmed up.

Reinartz told the commission that he decided there should be a more detailed discussion of the problem before he told Aldrich. But after the late-night telephone conference in which Thiokol reversed its recommendation, Reinartz said he felt it was no longer necessary to tell Aldrich, a member of what NASA calls its Level 2 management.

"In hindsight," Reinartz said, "it may have been better to inform Level 2 of the decision."

Reinartz told the commission that he knew of no previous situation in which a contractor recommended "no launch" and subsequently changed its mind.